Apple is expected to unveil a new line of iPhones next week at its annual September event.

Walkley says he expects two premium iPhones and a more affordable unit to be revealed at the event, helping "drive a continued strong upgrade cycle to higher margin and higher [average selling price] iPhones."

A customer purchases the new iPhone X at an Apple store on November 3, 2017 in Palo Alto, California.

Apple shares have been on fire lately and will add to their gains as the company's flagship product, the iPhone, increases its market share, Canaccord Genuity predicts.

Analyst T. Michael Walkley increased his price target on Apple's stock to $250 from $220, implying a 10 percent jump from Friday's close of $227.63. At one point Tuesday, Apple shares rose more than half a percent to around $229, a record high.

"Given the strong consumer satisfaction with iPhones, we anticipate Apple will continue to grow its global share of the premium smartphone market," Walkley said in a note Monday.

Apple is expected to unveil a new line of iPhones next week at its annual September event, where the company reveals a slew of upcoming products. Walkley said the event could lead to further market-share gains for Apple, further lifting the stock.

"We anticipate two new OLED screen iPhones and a more affordable LCD iPhone will launch in September 2018 to help drive a continued strong upgrade cycle to higher margin and higher [average selling price] iPhones," Walkley said.

IPhone sales have been the main driving force for Apple shares since their release in June 2007. In that time, Apple's stock has skyrocketed more than 1,200 percent. The stock is up more than 35 percent this year and hit reached $1 trillion in market cap last month.

Walkley said his surveys show iPhone sales are "resilient" heading into the event, and he estimates iPhone users will exceed 700 million by year-end. "This impressive installed base should drive strong iPhone replacement sales and earnings, as well as cash flow generation to fund strong long-term capital returns."

"With a mature smartphone market, we believe Apple has locked up strong share of the premium tier market and will continue to dominate highend smartphones sales and capture the vast majority of smartphone profits for the next several years," Walkley wrote, who also reiterated his buy rating on the stock.